(a) Field of the Invention
The present invention relates to a protective reel cover for an optical fiber and, more particularly, to the structure of a protective reel cover detachably fixed onto a spool for winding thereon an optical fiber to protect the optical fiber in association with the spool.
(b) Description of the Related Art
An optical fiber is generally wound on a spool after the manufacture thereof, and protected against an external force by the spool and an associated cylindrical protective cover detachably fixed onto the spool. The protective cover generally includes a pair of half-cylindrical cover members, which are coupled together at one of edges of the cylindrical surfaces by a hinge and also fixed together by the locking mechanisms at the other of the edges, thereby forming a cylindrical shape. A technique using the locking mechanism in a protective cover is described, for example, in a literature entitled “ABS Rib-Flanged Shipping Spool And K-Resin Spool Cover”, Corning Application Note AN04 issued in April, 1991.
FIG. 8 shows a portion of a protective cover having a locking mechanism similar to the locking mechanism described in the above literature. The protective cover 30 includes a pair of locking mechanisms, which are disposed at opposing edges of the cylindrical protective cover 30 and aligned in the axial direction thereof. The locking mechanisms each include a receiving member 32 fixed onto one of cover members 30A and 30B, and an engagement member 33 fixed onto the other of the cover members 30A and 30B. The engagement member 33 has thereon a locking protrusion 34 at the tip thereof for engaging with the receiving member 32 after insertion of the tip portion of the engagement member 33 into the receiving member 32.
For locking together both the cover members 30A and 30B, an operator allows both opposing edges of the cover members 30A and 30B to come close to each other, while allowing the engagement member 33 to be slightly deflected toward a fixing surface of a handle 35 for the protective cover 30. After the locking protrusion 34 of the engagement member 33 is allowed to pass through the receiving member 32 by the operator, the rear end of the locking protrusion 34 engages with the far edge of the receiving member 32 due to an elastic function of the engagement member 33, thereby locking together both the cover members 30A and 30B.
For releasing the locking mechanisms of the protective cover 30, it is necessary for the operator to press the locking protrusion 34 of the engagement member 33 of one of the locking mechanisms by using a left hand, for example, to press the locking protrusion 34 of the engagement member 33 of the other of the locking mechanisms by a right hand, and also to pull the opposing edges away from each other. Use of both the hands is sometimes difficult to the operator handling the optical fiber. That is, there is a request for handing the protective cover by one hand in the release operation for the locking mechanisms.
Patent Publication JP-2001-2323A describes a protective cover having a locking mechanisms capable of being released with ease. FIG. 9 illustrates the locking mechanisms of the protective cover described in the patent publication. The locking mechanisms each have a receiving member 42 and a hook member 43. The hook member 43 is configured by a leaf spring having a shape of U-character, and has a locking protrusion 44 at the tip thereof.
For locking together both the cover members 40A and 40B, it is sufficient for an operator to only allow the opposing edges of both the cover members 30A and 30B to come in contact with each other, with the other opposing edges being fixed by a hinge not shown. The hook member 43 is inserted into the receiving member 42 to allow the locking protrusion 44 to pass through the receiving member 42, whereby the locking protrusion 44 of the hook member 43 engages with the receiving member 42 to thereby lock together both the cover members 40A and 40B.
In the protective cover 40 described in the patent publication, it is easy for the operator to release the locking mechanisms, and thus the protective cover 40 is superior in the handling capability of the locking mechanisms. However, the hook member 43 protrudes from the surface of the handle 45 with a relatively large dimension. This may cause an inadvertent touch of the hook member 43 by an operator to result in release of the hook member 43 from the receiving member 42. If the hook member 43 has a relatively large elastic force to avoid such a situation, the handling capability will be degraded.